The present invention refers to a method for transferring at least one liquid component from a remote source to a metering pump assembly and to a dispensing assembly for carrying out the method, comprising a metering device for at least one liquid component with a metering pump and a remote source for each component.
State of the art metering and mixing machines as commonly used for dispensing two component reactive resins systems such as epoxies, polyurethanes, silicones, acrylics and polysulphides, because of their size in having two chemical reservoirs and a metering system, usually have to be distanced well away from the point of resin mixing and use. It follows, therefore, that the individually metered resins have to be transferred through hoses to that point and because most resin systems are very resistant to flow, they require high pressure for that transfer. Also, because most resin systems are somewhat compressible, it is necessary to use small hose bores so as to minimise their individual content volume compression/decompression and smaller bores demand even higher pressures.
In addition, metering accuracy can be further affected by hose wall flexibility with expansion and contraction according to pressure changes, thus causing compression and decompression of their resin contents during the intermittent starting and stopping of flow. In order to counter all of these disruptive characteristics, sophisticated valves are usually fitted at the hose ends so as to maintain the high pressure within the hoses when metered flow has been stopped. However, this valving brings the additional disadvantages of restriction to the resin flow as well as additional complexity and cost.